| Rural settlements are the places for human habitation. They are the carriers for farmers to live and product, which directly contact with human beings and environmental systems, represent relatively harmonious human settlements in the specific environment and reflect regional natural environment, product environment and traffic environment comprehensively as a kind of spatial units. And the exchange of material, energy and information of human beings and environment are achieved by the living environment. Karst regions of Chongqing municipality are one of concentrated distribution in large areas of Karst regions in southwest China. Natural characteristics of Karst regions are mountainous and uneven which determine the fragility of its environment and furtherly determine the limited capacity of environment surrounding rural settlements. Therefore, in the background of building new countryside policy in China, this paper discussed the relationship between distribution of rural settlements and its surrounding environment such as natural environment, product environment and traffic environment in different geomorphic regions, which contributed to enriching the theory of rural settlements, guiding the construction of rural settlements in Karst regions, improving the local living environment and ecological environment, promoting the preparation of the village planning and landuse planning, and optimizing the living environment and agricultural production. In recently, researches on rural settlements in Karst regions have been focus on spatial distribution of them with the macro perspective, and only a little research has been devoted to studying interaction between distribution of rural settlements and the surrounding environment in village scale. So, taking rural settlements of Tuanjie village, Yuchi town, Shizhu county as Karst valley, Yizhong village and Xinying village, Meijiang town, Xiushan county as Karst hilly area, and Qinggang village, Hefeng county, Fengjie county as Karst mountainous as examples. Distribution of rural settlements and the surrounding environment including natural environment, product environment and traffic environment in different geomorphic regions were analyzed, with the assistance of spatial analysis by GIS, correlation analysis and regression analysis by SPSS, applying the methods of distribution index, information entropy, box-counting dimension, spatial autocorrelation analysis, spatial structure analysis and landscape ecology. The main results showed as follows:1. Relationship between distribution of rural settlements and land form morphologicRural settlements were consistent basically in the distribution of quantitative and spatial in the study areas. In the Karst hilly area of Shizhu, the higher frequency and orderliness of rural settlements distribution mainly located in terrain niche with elevation950-1000m, slope5-15degree, aspect E, SW, NW, hypsography0.5-1.0m, surface roughness1.00-1.05, both slope of aspect and slope of slope0-5degree, respectively. In the Karst hilly area of Xiushan, the distribution of rural settlements primarily scattered in regions with elevation340-540m, slope0-15degree, aspect N, W, NW, hypsography0.0-0.5m, surface roughness1.00-1.10, both slope of aspect and slope of slope>25degree, respectively. In the Karst mountainous of Fengjie, the higher frequency and orderliness of rural settlements distribution principally situated in terrain niche with elevation550-750m, slope5-15degree, aspect N, NE, hypsography0.0-0.5m, surface roughness1.00-1.05, both slope of aspect and slope of slope>25degree, respectively.Related analysis of SPSS showed that in the Karst hilly area of Shizhu, rural settlements distribution was negative correlation with elevation, slope, hypsography, surface roughness, slope of aspect and slope of slope, but slope actually was positive correlation. Among them, the correlation between rural settlements distribution and slope, surface roughness reached the most significant level, and aspect, hypsography to reach significant level. In the Karst hilly area of Xiushan, the distribution of rural settlements and elevation, slope, hypsography, surface roughness were negative correlation, but didn’t reach significant level, and aspect, slope of aspect, slope of slope were positive correlation, but didn’t also reach significant level. In the Karst mountainous of Fengjie, rural settlements distribution was negative correlation with elevation, aspect, slope of aspect and slope of slope, but rural settlements distribution was positive correlation with slope, hypsography, surface roughness. Then the correlation between rural settlements distribution and elevation, aspect, hypsography, surface roughness reached the most significant level, and slope to reach significant level.Regression analysis of SPSS indicated that in the Karst hilly area of Shizhu, the regression equation between rural settlements distribution and slope, aspect, hypsography, surface roughness respectively were constructed to achieve significant level. Among them, with the increasing aspect, quantitative and areas of rural settlements increased gradually, but which were declined with the increase of landform morphologic factors such as elevation, slope, hypsography, surface roughness, slope of aspect and slope of slope. However, in the Karst hilly area of Xiushan, the regression equation between rural settlements distribution and landform morphologic factors such as elevation, slope, aspect, hypsography, surface roughness slope of aspect and slope of slope were constructed not to achieve significant level. In the Karst mountainous of Fengjie, elevation was the most important factors to influent the distribution of rural settlements, and then followed by aspect, hypsography and surface roughness. Except for slope of aspect and slope of slope, the regression equation between rural settlements distribution and landform morphologic factors such as elevation, slope, aspect, hypsography, surface roughness were constructed to reach significant level. Moreover, with the increasing elevation and aspect or the increase of slope, hypsography and surface roughness, areas of rural settlements were declined or increased.2. Relationship between distribution of rural settlements and farmlandsGeneral, small concentration of large dispersion was the characteristics of landscape spatial patterns in the study areas. In the Karst hilly area of Shizhu, irrigation terrace and upland field were absolutely essential landscape in this region. Moreover, irrigation terrace, upland field and woodland were in dominant position in the Karst hilly area of Xiushan. But in the Karst mountainous of Fengjie, the main landscape patterns were upland field and woodland. As a whole, the proportion of rural settlements were low, which indicated that the distribution of rural settlements were relatively sparse. Among them, in the Karst hilly area of Shizhu, it was4.56%, and the highest in the three study areas. Then the proportion of rural settlements was3.70%and0.89%in the other two study areas, respectively. The ratio of arable lands and rural settlements were15.63,13.94and20.23in the three research districts, respectively. The results showed that the relationship between proportion of rural settlements and ratio of arable lands and rural settlements were inverse basically in Karst areas.The relationship between distribution of rural settlements and farmlands, in the concrete, patch areas of rural settlements were different in different buffer distance, landuse type and geomorphic regions. From the total areas, patch areas of rural settlements became smaller and smaller with the increase of buffer distance because farmlands should be always managed well and thus could not be too far away from rural settlements in Karst regions of dense population but less land. In the Karst hilly area of Shizhu, mean patch areas of rural settlements were below0.1hectare, and the smallest in the three research districts. But mean patch areas of rural settlements varied from0.1023hectare to0.1750hectare in the other two research regions. Mean shape index of rural settlements varied from1.19to1.40, and the area weighted mean patch fractal dimension were below1.15, among them,1.1385was the biggest value and1.0824was the smallest. This was because the patch of rural settlements was artificial patch and the influence of human activities, resulting in more regular in its shape and smaller in its fractal dimension. Moreover, the mean nearest neighbor distances of rural settlements were uneven, among them, the largest was up to82.76meter, but the minimum was only11.18meter, which showed fragmentation and dispersion were characteristics of rural settlements distribution in Karst regions. The contagion index indicated that the connectivity was weak, agglomeration was low and fragmentation was large among rural settlements. Together, spatial convergence was very strong in the distribution of rural settlements and farmlands, and the production orientation of rural settlements was showed.3. Relationship between distribution of rural settlements and rural roadsOn the road grade, production roads were the main roads in the study areas. On the road network, the landscape connectivity level was the highest in the Karst hilly area of Shizhu, and which was the lowest in the Karst mountainous of Fengjie. In the Karst hilly area of Xiushan, a circuitry index,β line-node ratio and y connectivity index were the largest, but which were the smallest in the Karst mountainous of Fengjie. On the layout of field roads, in the three areas, a circuitry index were zero, which indicated field roads network were no loop.β line-node ratio and y connectivity were roughly the same, which showed that the connectivity level of field roads were basically in line. On the layout of production roads, in the Karst hilly area of Shizhu, a circuitry index didn’t form a loop, and β line-node ratio was less than one, which indicated that production roads formed a tree pattern. Whether it was a circuitry index, or β line-node ratio and y connectivity, they were relatively close in the Karst hilly area of Xiushan and the Karst mountainous of Fengjie, which explained that the complexity of the network was no significant difference.Fractal dimension showed the system of rural settlements in development was weak, and the ability of occupying space was also weak. Specifically, in the Karst mountainous of Fengjie, fractal dimension was0.9208, which indicated that rural settlements developed well best. In the Karst hilly area of Xiushan and the Karst hilly area of Shizhu, fractal dimension was0.9152and0.8991respectively. Learned from the global spatial autocorrelation analysis, Moran’s I coefficient was0.0166,0.0370and0.2032respectively in the three study areas. And the results of local spatial autocorrelation analysis and global spatial autocorrelation analysis were similar. That is to say, the correlation of rural settlements distribution was mainly positive and there was certain spatial aggregation, but the relativity was the strongest in the Karst mountainous of Fengjie and that was the weakest in the Karst hilly area of Shizhu.The relationship between distribution of rural settlements and roads, as a whole, the closer the road was, the more intensive the distribution of rural settlements was, and the more regular the shape of rural settlements was. Specifically, the scales of rural settlements were different within different buffer distance of different road grades in different geomorphic regions. From the total areas, a decreasing trend was showed in distributing of rural settlement, but the areas of rural settlements were up to9.53hectare in buffer distance more than150meter on field roads grade, and that were6.38hectare in buffer distance more than200meter on production roads grade in the Karst hilly area of Xiushan. This was indicated the impact of roads on the distribution of rural settlements was the weakest in the three study areas. The mean patch areas of rural settlements, in addition to be above0.1hectare within several buffer distances, the remaining were below0.1hectare, which showed harsh natural conditions made less lands that could be available for human, and resulting in the less of rural settlements in Karst regions. Moreover, the mean shape index and area weighted mean patch fractal dimension were below1.40and1.14, respectively, which showed the influence of human activities was so intensive that the shape of rural settlements was more regular and the fractal dimension was also smaller in Karst regions. From the mean nearest neighbor distance and contagion index, in the Karst hilly area of Xiushan, the distribution of rural settlements was the most intensive and agglomeration was also the most highest, and that was the most sparse in the Karst mountainous of Fengjie. This showed adequately the distribution of rural settlements was compatible with the local fragile environment in Karst regions.To sum up, this paper revealed the impact of environment to rural settlements, through analyzing the interactional relationship between the distribution of rural settlements and three environmental aspects including natural environment, product environment and traffic environment, with the perspective of the village scale. In a sense, the distribution of rural settlements is affected by natural environment, product environment, traffic environment, social-economic environment and human environment. But the thesis only discussed the interactional relationship between the distribution of rural settlements and three environmental aspects including natural environment, product environment and traffic environment. To recognize the distribution of rural settlements in Karst regions better, the factors such as sense of family and provincialism, population distribution and local economic development should be considered. |
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